Kaposi – Related Virus More Common Than Thought

Kaposi-Related Virus More Common Than Thought
A virus associated with a cancer common in AIDS patients may infect more of the general population than previously believed, say researchers from the Universita Cattolica del Sacro Cuore in Rome, Italy.

Reporting their findings in the April issue of the Journal of Clinical Microbiology, the researchers found human herpesvirus-8 (HHV-8) infection — a possible cause of Kaposi’s sarcoma — in almost two thirds of the healthy Italians in their study. A previous US study found that about 20% of blood donors are positive for the virus.

The investigators studied the prevalence of HHV-8 in 50 AIDS patients with Kaposi’s sarcoma (KS) and 50 cancer-free, HIV-negative patients from central and southern Italy.

Kaposi’s sarcoma is a cancer characterized by malignant cells found in the tissues under the skin or in mucous membranes. It causes red or purple patches (lesions) on the skin, and often in other sites as well, including the lungs, intestinal tract and lymph nodes.

The researchers found that all of the KS patients were infected with the virus. Surprisingly, however, they also found evidence of HHV-8 infection in 32 of 50 of the healthy participants.

“This data suggests that HHV-8 infection is not restricted to Kaposi’s sarcoma patients,” the research team led by Dr. Paola Cattani says. “And that the prevalence of HHV-8 infection in the general population may be correlated with differing rates of prevalence of KS in different parts of the world.”

Based in part on their results, and on several earlier reports suggesting multiple modes of transmission, the Italian researchers evaluated nonsexual transmission of HHV-8.

They tested for the virus in the saliva, urine, and tonsils of both the KS patients and the healthy participants. In the KS patients, the researchers found evidence of viral infection in 43.7% of the tonsillar samples, 45.8% of the saliva, and in 8.3% of the urine samples.

In contrast, they found that none of the saliva or urine samples from healthy participants had evidence of viral infection, and only one tonsil sample produced a positive result.

The researchers conclude that the virus may be transmitted in a dormant form that requires other factors to activate it.

Because evidence of the virus appeared equally in the tonsillar and saliva samples among the KS patients, the researchers suggest that the virus replicates in tonsils, part of the lymph system, and then sheds into saliva, which could contribute to HHV-8 transmission.

Dr. David Koelle, a virologist at the University of Washington in Seattle, led the team cited by the Italian researchers that first found large amounts of HHV-8 DNA in the saliva of KS patients.

Koelle said in an interview with Reuters Health that while the Italian study confirms his team’s findings of possible oral transmission of the virus, it does not suggest any clinical significance for healthy people.

“There are geographical differences in the prevalence of HHV-8 infection and we have long known Italy is a hot spot,” Koelle said.

“The implications of this study are really that you first must have HHV-8 infection and second a bad immune system to get Kaposi’s sarcoma. So even if the prevalence (of the virus) is higher in a certain area, the medical consequences for healthy people are not that great,” he explained.